Telephone pulse repeater actuated by break period



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FRANK KESS LER ATTORNEY Patented Mar. 14, 1950 TELEPHONE PULSE REPEATER ACTUATE BY BREAK PERIOD Frank Kessler, Lombard, Ill., assgnor to Automatic Electric Laboratories, Inc., Chicago, Ill., a corporation of Delaware Application August 30, 1946, Serial No. 694,043

` 4 claims. (o1. 179-16) The invention relates in general to automatic telephone systems, and more particularly, to a novel circuit arrangement for an impulse cor recting repeater.

The main object of the invention is to provide an impulse repeater circuit arrangement whereby correction of impulse transmission may be accurately and efficiently accomplished.

The impulse repeater disclosed herein is of the type which is arranged to repeat a corrected impulse only after the corresponding incoming impulse has been terminated, the open interval of the corrected impulse being independent of the duration of the open interval of the incoming impulse. The present invention is in the nature of an improvement on the impulse repeater disclosed in the Lomax-Jones application Serial #666,283, now Patent Number 2,487,252, granted November 8, 1949, filed May 1, 1946.

A feature of this invention is the manner in which a relay in the repeater is arranged to operate responsive to seizure of the repeater to vclose the repeater outgoing circuit, the same relay being further operated to determine the duration of the break of the corrected impulse transmitted over the circuit by the repeater.

A further feature of the invention provides for energization of a relay, for the purpose of controlling a pair of relays to transmit corrected impulses in the manner described above, on the break period of the initial impulse and to be energized subsequently on each successive break.

Another feature of the invention is the provision of means in an impulse repeater of this type for quickly releasing the equipment which seized the repeater on release of the repeater line relay and then in a subsequent operation providing protection for therepeater against seizure by other automatic switches over the incoming side until the equipment on the called side of the repeater has released.

A further feature of the invention is the provision of means in the repeater for completing a preenergizing circuit over the trunk line to a distant associated automatic switch during the break period of each corrected impulse.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification and the accompanying drawing.

Referring now to the drawing, the automatic telephone system there illustrated comprises a subscriber substation a group of automatic switches including selector switch 2, repeater circuit 3, selector switch 4, connector switch 5, and subscriber substation 6. The selectors and connectors in the system are of the conventional Strowger type.

The repeater circuit, as illustrated, comprises a relay group including a reverse battery relay I0, a line relay 20, hold relays 30 and 40, polarized relay 50, hold relays BIJ and 1U, trigger relay 80, and timing relays 90 and |00, resistances I4, I I5, IIS, ||8, busy key IIB, and a control network connected and arranged in a manner more fully described hereinafter. The substations shown are of the conventional automatic type comprising a telephone instrument, impulse sender and Ilnger.

Considering now the extension of a call from subscriber substation I to subscriber substation 6. The call is initiated in the usual manner when the subscriber removes the receiver at substation The calling subscriber then dials the coded number assigned to substation 6 whereby selector 2 will be operated to seek an idle repeater circuit. Assuming the repeater circuit 3 illustrated in the drawing is idle and is the circuit selected by the selector 2, line relay 20 in the repeater circuit will be energized over incoming-lines IIB, III and contacts Il and I3. Relay 20 operates and at its contacts 2| completes a circuit to hold relay 30. Relay 30 operates and at its contacts 3| prepares a point in the circuit for relay 80, at its contacts 32 completes a circuit to the iirst winding of polarized relay 5|] over contacts 63 and also completes a circuit to relay Illll over contacts 95, at its contacts 33 completes a circuit to relay 40, and at its contacts 34 places ground on the incoming C' lead I Il thereby rendering the repeater busy to seizure attempts by associated selectors. Relay |00 operates and at its contacts |0| and |02 prepares a bridge circuit to selector 4, at its contacts |03 prepares a point in the circuit for relay 90, at its contacts |04 breaks the holding circuit for relay 30 which existed over contacts 32 and |04, and at its contacts |05 prepares a point in a. holding circuit for `relay to extend over contacts 82 and 32. Relay 40 operates at the same time and at its contacts 42 connects the selector 2 to selector 4 through the repeater and also completes the bridge circuit which ex tends over conductor H2, contacts 42, 9|, |0I, resistance I I8, the second winding of polarized relay 50, contacts 13, |02, 92 and conductor ||3 to energize the line relay in selector 4. Relay 50 is a shunt field polarized relay of the type disclosed in the patent to Erickson, No. 1,544,300, granted June 30, 1925. The windings of relay 50 at this time are energized differentially and the relay is therefore ineffective to operate. Relay 4G at its contacts 43 prepares a circuit having no function at this time, at its contacts 44 completes a holding circuit over contacts 2l to relay 3&3, and at its contacts 45 completes a point in chain circuit |2. y

When the calling subscriber dials, the calling line loop is interrupted a number of times corresponding to the value of the digit and as a result, the line relay 2U is ole-energized a number of times to produce in combination with the associated repeater circuit a like number of interceptions in line conductors H2. and H3, the outgoing interruptions being of a certain time length regardless of the duration of the break period of the incoming impulses. Each interruption is repeated only after the corresponding incoming interruption has been terminated. This repeating operation will now be described. On the rst incoming interruption relay 2 releases andat its contacts 2l breaks the original operating circuit to relay 3Q, which being slow to release remains operated, and at its contacts 22 completes a circuit to trigger relay t0 over contacts 51,22, i5 and 3l. Trigger relay 3! operates and at its contact 8l prepares a circuit for relay SG, at its contacts 82 completes a selfholding circuit over contacts 32, 165 and 32, and at its contacts 83 completes an operating circuit to relay lli. Relay 'I0 operates and at its contacts Il and 'l2 completes the battery pulsing loop which passes over outgoing conductor H2 and H3 and resistances H4 and H5. These resistances may be adjusted to provide the proper values suitable for either a battery pulsing or a loop pulsing arrangement. Relay lil also, at its contacts '13, breaks a point in the holding bridge circuit described heretofore, opens the circuit of the second winding of relay 5t, and connects battery over conductor H3 to the line relay in selector 4, at its contacts '54 completes a circuit for relay Bil, at its contact l5 completes a holding circuit for relay 45 over contacts 43 and l5, and at its contacts breaks a circuit not having ay function at this time. Relay @Il operates and at its contact GI breaks the connection between incoming conductor I lil and outgoing conductor H2, kat its contacts S2 breaks the connection between incoming conductor IH and outgoing conductor H3, at its contacts 63 breaks the circuit to the first Winding of relay 50, and at its contacts 64 connects an adjustable secondary ground to the outgoing conductor H2 which is effective to cause the line relay in selector 4 to act more quickly on receipt ofthe make period of each outgoing impulse.

Line relay now operates responsive to the first make after the iirst break oi the received impulses. Relay 2D, at its contacts 2l, completes a circuit over contacts l', 2l, i133, 8l to relay 93, at its contacts 22 breaks the operating circuit to relay 80 Whichholds over contacts 82, IGS, and 32. Relay B Operates and at its contacts Si opens a point in the outgoing circuit over conductor H2 to selector 4 and removes resistance H6 from the outgoing line to allow quick release of the` line relay in the selector, at its contacts 92 opens a point in the outgoing circuitto selector 4 overv conductor H3, at its contacts 93 short circuits its own winding thereby making it slow to release, at its contacts 94 completes a self-holdingcircuit over contacts 32'; 94; land 8|; and vat itslcontacts 95 opens theoper'ating: circuit to relay itt; Relay |00 releases and at its contacts Il and m2 opens further points in the outgoing circuit to selector 4, at contacts H33 opens the operating circuit to relay 90, at contacts H14 closes a holding circuit to relay 3o over contacts |04 and 32, and at contacts i opens the holding circuit to relay Sii. inasmuch as relay B is short circuited, its release time will be of longer duration than relay 88. Relay 8o releases and at its contacts 8l opens a further point in the circuit to relay 9U, at its contacts 82 opens a further point in its holding circuit, at its contacts 33 opens the operating circuit to relay lll. Relay lll is slow to release and Willltherefore hold for the duration of impulses, being aided during each break period ofthe incoming impulses by energization of relay 8U. Relay S0 releases and at its contacts 9i and 92 close a point in the outgoing circuit `to selector 4l, and inserts resistance H6 in series with the line, at its contacts 93 opens its own short circuit, at its contacts @il opens a further point in its self-holding circuit and breaks the holding circuit to relay 30 extending from ground over contacts 32 and 94, and at contacts Q5 completes an operating circuit to relay l Bil. Relay 30 remains energized over contacts il and 2i. Relay IBG operates and at its contacts Il and H32 closes the circuit over conductors H2 and H3 to selector 4, at its contact H33 closes a point in the circuit to relay S5, atits contacts itt opens the holding circuit to relay Bt over contacts 32 Vand m4, and at contacts 105 prepares a holding circuit for relay 80. The outgoing interruption was transmitted therefore, only after the corresponding incoming impulse was completed. The length of the outgoing interruption, as vnoted in the. above description, was determined by the release time of relay 90, plus the release time and the operate time of relay lill), the length of the outgoing interruption therefore being determined independent of the incoming impulse duration. The repeater circuit is operative to repeat the dialed digits as narrated previously herein, and is effective thereby to complete the connection to the desired subscriber A short interval after the digit group is transmitted relays 89 and 'it deenergized. Relay l releases and at its contacts Tl and 'l2 removesthe battery pulsing loop fromv the line and prepares a point in the connection through the repeater, at its contacts 14 opens the operating circuit to relay BUand at its contacts 16 prepares a point in the circuit to'relay lll. Relay 6G releases and at its contacts 6l and 82 completes the subscriber connection through the repeater to the called subscriber, at its contacts 63 completes an operating circuit to the rst Winding of relay 5G 'over contacts 32, and at its contacts 64 removes the resistance H6- from the line circuit. Relays 20, 3D, 4i! and lll remain in the operated condition and the connection is now extended from subscriber l over selector 2, the incoming conductors l lll, l H of repeater circuit 3, contacts 6l, and 52, 13, lill and m2, 9i and 92, 42, conductors H2 and H3 of the repeater, selector It, connector 5, to subscriber 5.

When the called .subscriberanswers the connector 5 in use reverses the direction of current ow over the conductors H2 and i i3, causing the energiaation of theV second Winding of relay E50. Relay 5S operates and at its contacts 5i completes a circuit to relay lo over contacts 43 and l. Relay lil operates and iat its contacts i2 and i4 reverses the direction of current flow in the calling subscribers line. Relays i0, 2li, 3l), so, 50 and ill@ are now operated.

When the calling subscriber restores his receiver, relay 20 deenergizes and at its contacts 2l breaks the operating circuit to relay 3U, and at its contact 22 closes a point in the circuit to relay Sii. After an interval, relay 3B releases and at its contacts 3l opens a further point in the circuit to relay Sii, at its contacts 32 opens the circuit to relays lll@ and 5I), at its contacts 33 opens the operating circuit to relay 40, at its contacts Sil momentarily removes ground from the conductor lll to provide time for release of previous switches,` and at rits contacts 35 reconnects ground to the conductor I I1 over contacts 43 and l5 to provide suicient time for the subsequent switches to release before seizure by a second subscriber. Relay 5U releases and'at its contacts 5l opens the operating circuit to relay l0. Relays iii and IDS release. Relay 40 after a short intervalreleases and further opens the trunk circuit at its contacts 42, atits contacts i5 opens the chain circuit, and at its contacts 43 removes ground from C lead ill to allow the repeater to be seized for subsequent connections.

If the called subscriber hangs up rst, relay 5i) releases and at its contacts 5| releases relay Ill. The set is restored to normal as before when the calling subscriber restores his receiver.

While particular embodiments of the invention have been illustrated, it is to be understood that numerous modifications in the details of arrangement may be resorted to without departing from the true spirit and scope of the invention as dened in the appended claims.

What is claimed is:

1. In combination with :a trunk line over which impulses are transmitted, each of said impulses having a make and break period, the ratio of said make to break periods being different at diiierent times, and impulse correcting repeater having incoming and outgoing connections connected to said trunk line, a selector having a line relay connected by a section of said trunk line to the outgoing connections of said repeater, means in said repeater responsive to each of said incoming impulses to transmit a corresponding corrected impulse to said selector only upon termination oi such incoming impulse, said means operative to cause each of said corrected impulses to have a predetermined break interval independent of the make to break ratio of said incoming impulses, said means operated to insert a resistance in said connection to said selector during the latter portion of each break period of the corrected impulses for the purpose of preenergizing the line relay in said selector, and operated to remove said resistance from said connection during the initial portion of each break period of the corrected impulses.

2. In combination with a trunk line arranged to receive impulses, said impulses having different break intervals at different times, an impulse repeater having its incoming and outgoing conductors connected to said line, a group of automatic switches connected to said incoming conductors over said line, another group of automatic switches connected to said outgoing conductors over said line, means in said repeater operative on seizure by one of the switches of said rst group to transmit corrected impulses over said outgoing line to the other of said group of switches only upon termination of the corresponding incoming impulse, said corrected impulse having a break period of predeof the" incoming impulses, said means operated on seizure of said repeater by a switch of said iirst group to busy the repeater circuit to other switches of said first group, said means operated on release of the connection to said repeater to remove the busy connection to said first group to permit release thereof and further operated to apply asecond busy connection to said rst group to prevent seizure of the repeater thereby before release of said second group of switches.

3. An impulse correcting repeater, incoming and outgoing connections for said repeater, means for seizing'said repeater over said incoming connections, a line relay vin said repeater energized by the seizure'of said repeater and deenergized and reenergized byimpulses transmitted over said incoming connections, said impulses having make and break periods of varying ratio, a rst and second pulsing relay in said repeater, a first circuit including make contacts on said line relay and back contacts on said iirst and second pulsing relays completed by the energization oi said line relay for initially energizing said rst pulsing relay, a second circuit including back contacts on said second pulsing relay for subsequently energizing said first pulsing relay independent of said line relay make contacts and independent of said back contacts on said iirst pulsing relay after the initial energization of said first pulsing relay, an operating circuit for said second pulsing relay, normally open contacts on said rst pulsing relay included in said second pulsing relay operating circuit and closed responsive to the operation of said rst pulsing relay to prepare said operating circuit of said second pulsing relay, means including said make contacts on said line relay and said normally open contacts on said iirst pulsing relay completing said second pulsing relay operating circuit each time said line relay is energized during a make period following a break period to energize said second pulsing relay, said back contacts on said second pulsing relay opening said first and second circuits to deenergize said first pulsing relay in response to the energizatio-n of said second pulsing relay, said normally open contacts on said first pulsing relay opening the operating circuit of said second puls-ing relay to deenergize said second pulsing relay in response to the deenergization of said first pulsing relay, said back contacts on said second pulsing relay reestablishing said second circuit of said iirst pulsing relay to reenergize said rst pulsing relay in response to the deenergization of said second pulsing relay, and pulsing contacts on said first and second pulsing relays included in said outgoing connections for transmitting corrected outgoing impulses having break periods determined solely by the operate time of said first and second pulsing relays.

4. In an impulse correcting repeater, incoming and outgoing connections for said repeater, means for seizing said repeater over said incoming connections, a line relay in said repeater initially energized by the seizure of said repeater and deenergized and reenergized by impulses transmitted over said incoming connections, said incoming impulses having make and break periods of varying ratio, a control relay and first and second pulsing relays in said repeater, a first circuit including make contacts on said line relay and back contacts on both said iirst and second pulsing relays completed by the energization of said line relay for initially energizing 7 saidz rst' pulsing s rel ay, aV second. circuit includ.- ing said back contacts-on said second pulsing relay for-*subsequentlyI energizing said rst pulsing relay independent of said linerrelay make'contacts andfindependent of said back contacts on saidrst pulsing relay alter; the initial-energize,- tionofrsaid rst pulsingrelay; an operating circuit for said-second pulsing relay, normally open contacts onv saidflrst pulsing relay included in said second` pulsing relay operating circuit and 10 closed responsive to vthe operation ofsaidiirst pulsing relay to prepare said operating circuit of said second zpulsingrelay, means yfor operating said controly relay -in response to leachdeenergization of said line relay during the break.- period of. each incoming impulse, make` contacts on `said control relay` and said makecontacts on said line and rst pulsing relaysl completing said second {puls-ing relay loperating circuit feach time said line relayis energized during a make period'fol-l lowing a break period to. energizeV said second pulsing-relay, said back contacts on said second pulsing relay opening said first and second-.circuits to' deenergize said rst pulsing relay :in-responseto the energization-of said 'secondfpulsing relay, said, normally open contacts on saidrst pulsing relaya,openingfsaid` operating circuit of said second pulsing: relay todeenergizesaid second pulsingrelay inresponse to the vd'eenergization. of; said rst puls-ingl relay, saidv back contacts: on .1 said' second: pulsing relay. reestablishing `said' vseconrlxcircnit-rto'reenergize said rst pulsingy relay in -s response. tot thel deenergization of' said second pulsing relay, and.` pulsing contacts'on` said-first andfsecond pulsingrelays included Vin',said"Aoutgiring"connection Afor transmitting correctedf; outgoing impulses having break periods determined solely by the operatetime otsaidrst'fand second pulsing relays.`

FRANKKESSLER.

l REFERENCES CITED i The Yfollowing'references arel of record'in the le of'this' patentz' UNITED STATES PATENTS Number Name Date 1,589,409 Miller -June 22, 1926 1,747,405 Beckerath Feb. 18, 1930 1,831,730- Ahlberg Nov; 10, 1931 2,061,802 Kroll et al. Nov. 24, 1936 2,428,550 Burgener Oct. 7, 1947 

